Collision detection is the determination of whether or not two or more entities make contact with each other during gameplay.

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Line segment / circle intersection - X value seems wrong?

Major Edit I'm making a Breakout clone, and having difficulty with collision detection between a circle and line segment. Apologies, my earlier question was a result of frustration and no sleep :) ...
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Circle-Line Collision Detection Problem

I am currently developing a breakout clone and I have hit a roadblock in getting collision detection between a ball (circle) and a brick (convex polygon) working correctly. I am using a Circle-Line ...
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2D circle / rectangle collision detection issue - brief overlap

I'm currently trying to build a Breakout clone as a first step into game development. I'm using the following collision detection code (adapted from ...
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4answers
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2D Platformer Collisions

I've basically asked this question before, and I know it's been asked probably a billion times, but I still can't seem to do it. All I want to know is how I should go about doing basic 4-way, ...
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1answer
512 views

Updating XNA BoundingSphere - sphere moves in opposite Y direction?

In my players update method I calc the new world matrix then I update a boudingsphere by: MyBoundingSphere = MyBoundingSphere.Transform(World); However when the the model's World has moved ...
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How can I implement fast, accurate 2D collision detection?

I'm well aware of how to detect if two or more 2D objects collide but I'm interested in how to decide whether to check for a collision. In previous projects, I just had every object check against ...
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How can I detect collision between a circle and a rectangle?

i'm trying to make a clone of brick breaker, one problem that i am running in to is to do with collision. i know how to detect if a collision has happened but i do not know how to check what side of ...
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2answers
521 views

How to detect collision with non-rectangular objects in 2D games?

Detecting collision with rectangular objects is quite easy. I am able to write simple tile based games. Now I want to learn to write non-tile based games in which objects may not be rectangular, for ...
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974 views

XNA: Perform Collision Detection Against 3D Scene Geometry

How would one perform collision detection between a simple scene like the one below and a simple object like a sphere? I assume the best solution would involve convex hulls in some way but I have no ...
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Basic 2D game collision

I've been trying to program a game for the past while and I can't ever figure out one thing: collision detection. I can get up+down and left+right to work, but when I put them together, they interfere ...
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4answers
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How to deal with corner collisions in 2D?

I'm writing a top down 2d XNA game. Since its my first I'm trying to write the physics and collision stuff myself to learn it. Whenever my player sprite character attempts to move into a position ...
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3answers
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Clean way to detect collision of object with box2d

I have been looking into box2d (in java with libgdx) lately and have been trying to create my own custom bounce effect (I increase the Restitution after the first bounce) To do this as a test I ...
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1answer
905 views

How to find which side of a collider has been hit from hit.normal?

In Unity3d, i can get the normal of the surface with which the collider collides using hit.normal, but is there a way to find which side has been hit what is provided bu Unity3d? One solution is to ...
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How can I set up a Pong-style game using the physics system in Unity?

I've just been using Unity and chose to learn it by making a Pong game which sounded simple enough as a "hello world" type of game. My goal was to try and encompass enough of the built in engine ...
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1answer
950 views

XNA Platformer Collision: PerPixel vs Rectangle

I'm writing a platformer engine with XNA and was wondering what method for handling collisions I should use. Would I be seeing some performance issues if I were to try and have PerPixel collisions? ...
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3answers
764 views

Polygon editor to draw collision data over image

I need an editor to plot a polygon over the texture for of a ship in my game. It would look like this.. Where the red is the collision outline and the image is the texture. I want to store the ...
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1answer
882 views

How to resolve collisions of compound shapes using SAT?

SAT is a decent way to determine collisions between arbitrary convex polygons. You'll even get the vector that is needed to resolve a collision. To resolve collisions between complex (non-convex) ...
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1answer
238 views

Collision Managers and bitmaps

I am rewriting a game I made to use a (custom) collision manager that uses the minimum displacement method. As of now, my simple manager can only recognize and act on a couple of shapes - Circles and ...
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1answer
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Sphere collision response

I have simple mechanism for testing of two balls colliding: private static boolean isColliding(float firstBallX, float firstBallY, double firstBallRadius, float secondBallX, float secondBallY, double ...
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1answer
983 views

Collision detection problem

I am a novice in android. It's my first game, so I am trying to make a frogger clone. I am getting a problem in collision detection. In logcat, even though the frog is not moving and not colliding ...
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3answers
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2D game collision response: SAT & minimum displacement along a given axis?

I'm trying to implement a collision system in a 2D game I'm making. The separating axis theorem (as described by metanet's collision tutorial) seems like an efficient and robust way of handling ...
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1answer
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Setting up collision using a tilemap and cocos2d

I'm building my first platformer using cocos2d and a tilemap. I'm having trouble coming up with a decent way of determining if the character is colliding with an object. More specifically, in which ...
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1answer
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What is wrong with my collision detection code?

I want to check collision detection between two bitmaps but I am not getting how to do it. I read several queries and tutorials but didnt get properly. I want to check by their width and height. I ...
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2answers
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Is it possible to have concurrent collision detection where every entity acts at exactly the same time?

There are many algorithms that can be used for collision detection. In many cases we check for an overlap in coordinates of an entity. If we make a triangle a,b and c. We have 2 entities at a and b ...
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1answer
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Am I going to regret using a color based collision detection system?

I'm just getting started build my first game with XNA (I'm experienced with C# but not games). I'm building a pretty simple top down 2d shooter. I read this tutorial on using a color based collision ...
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2answers
678 views

HTML5 collision with images

Can anyone please help me out with a small test game I'm creating. I'm basically creating this game to learn a few things about HTML5 and so far it's all been good. I've been able to create a canvas ...
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How do I find the point of impact with 2D per-pixel collision detection?

I'm creating a platformer and have implemented per-pixel collision detection. However, this has caused 2 obstacles that I've yet to figure out. The first obstacle, which this question is about, is ...
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2answers
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Algorithm to fit shapes to 2D grid?

Let's say you have an n-by-m grid. Some squares are occupied, some are not. You want to know where in the grid you can fit arbitrary shapes such as to not hit an occupied square. The shapes would ...
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3answers
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How to handle platform collisions in a 2D game?

If I have a map in my platformer game and I want my character be able to jump on some platform, for example. Is there an easy way to tell the game where the platforms are and where the player can jump ...
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1answer
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How can I cancel a contact in a b2ContactListener?

To know when contacts happen we can derive from b2ContactListener and implement our own solution which is great. I'm wondering is there anyway we can cancel a contact, that is to say when we hit begin ...
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3answers
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Collision resolution in case of collision with multiple objects

I have static objects and movable objects. The collisions are detected using the separating-axis-theorem. For example, in this situation I have two static objects (in red): and a movable object ...
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1answer
896 views

Can you help with collision detection and response in a 3D car racing game?

I am trying to implement the collision detection and response in 3D car racing game. I have a car model, for collision I am assuming my car as a cuboid. my collision detection with walls is quite ...
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4answers
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Momentum and order of update problems in my physics engine

This question is a "follow-up" question from my previous one, regarding collision detection and resolution, which you can find here. If you don't want to read the previous question, here's a ...
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C# XNA Framework Paddle Collision Problems

I am trying to make a pong game that uses a burger as a ball and a plate as its paddle. I have everything right except that the burger goes right through the plate. Can anyone help me? using System; ...
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974 views

How to coordinate sprites, player's position and collisions in a Bomberman-like 2D game?

I'm programming a Bomberman in Java (my first game) and I'm having problems with the player's sprites and position in the map. I'm using a 2D integer array to represent: Unbreakable blocks ...
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2answers
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pathfinding with obstacles in a Warcraft 3 like game

Consider A* searching on a tile based map. A straight forward code would be: If there is an unit inside that cell, then it is unreachable, this is ok. But there is map resolution issue. When I look ...
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2answers
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Checking for Weapon Collision in a 2D overhead RPG game

I'm starting development on a 2D overhead RPG game, and am wondering what the best approach for handling weapon collision and dealing damage to enemies is. I'm currently using a basic ...
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1answer
619 views

Need help with collision detection/resolution in a 2D simulation of 'worm-like' creatures

(originally posted this on regular stack overflow, somebody pointed this forum out :-) ) Hi there, I'm implementing a physics engine for the simulation of worm-like creatures. Problem is, is that ...
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2answers
522 views

Best way to traverse triangles in a mesh

I'm implementing non-projective decals. As described in many places (ie: lengyel in the gpg2) I first need to detect all triangles that lie within some sort of frustum. Besides obvious brute-force ...
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Android Fling Gesture, Animation And Collision - Resources?

I'm starting work on a 2D Android game where the player will put their finger on a game piece and do a fling gesture to throw the piece across the gameboard. I've gone through some Android ...
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2answers
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Is there a good way to get pixel-perfect collision detection in XNA?

Is there a well-known way (or perhaps reusable bit of code) for pixel-perfect collision detection in XNA? I assume this would also use polygons (boxes/triangles/circles) for a first-pass, quick-test ...
2
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2answers
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Pygame How To Use Collision?

Can someone tell me how to implement collision in Pygame? For example I have a sprite called A and another one called B. How do I detect if they collide in Pygame?
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4answers
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2D Spatial partitioning alternatives to spatial hashes and quadtrees

I've been trying to implement a spatial partitioning algorithm in my game, but both spatial hashes and quadtrees aren't what I'm looking for. My level size is not supposed to have a limit (only Int32 ...
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1answer
310 views

Insert object at index, when two objects collide

I have two arrays: one for projectiles, and one for targets. Every target and every projectile has tag, and a tag with color (source code I took from Ray Wanderlich). In my small game, when a ...
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6answers
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Collision 100% avoidance implementation

I'm an absolute beginner with game development and all I know about collision avoidance/resolution, I learnt it on or through this site in the past week... so don't hesitate to correct me if what I'm ...
2
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2answers
364 views

Handling collision with 2D surfaces and player sprite

What's the best way of representing surfaces in a 2d top down racing game? I'd like paved and dirt surfaces in my game to have different friction properties. Would you break up the map into a grid and ...
2
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4answers
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How do I detect pixel-level collision using andEngine?

I'm developing a game for Android using andEngine, and I need to detect collisions only when two objects visually collide (not in blank space of the image). In J2ME, I'm able to do that using ...
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Are there well-known algorithms for fitting a polygon to an arbitrary shape?

I'm using the Chipmunk physics engine to make the levels for a 2D C game. I'd like to be able to fit a polygon to an arbitrary shape to serve as the collision mask. Given a black and white collision ...
5
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2answers
868 views

Collision response for 2D racing game

The title is fairly self-explanatory. I have a 2D racing game that utilizes per-pixel collision detection (the track is essentially two bitmaps, one for the graphics, one for collision data). The ...
48
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7answers
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2D Platformer AABB collision problems

I have a problem with AABB collision resolution. I resolve AABB intersection by resolving the X axis first, then the Y axis. This is done to prevent this bug: http://i.stack.imgur.com/NLg4j.png ...